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Electric Water Pump & Controller
aksman - 3/12/20 at 04:19 PM

I am going to use an electric water pump on an A Series 1275.
Are there any cheaper alternatives to the Davies Craig water pump?
Would an auxiliary water pump from a 2 to 3+ litre BMW / Merc etc. be powerful enough as an alternative?
Are there any cheaper alternatives to the Davies Craig Controller?
I am particularly keen on being able to auto-control the speed of the pump in relation to the varying water temperature, rather than a simple thermostat.
Any info and suggestions woud be very welcome.
TIA


[Edited on 3/12/20 by aksman]

lsdweb - 3/12/20 at 05:12 PM

The Pierburg pumps (BMW etc) are very good and you can either buy a controller (Tecomotive TinyCWA) or you could make your own (Arduino etc). My friend and I have made our own (well he has and I'm sort of copying him but using an ESP32 as it has built in CAN) and his works well. My plan is to do exactly as you said and make the pump a touch more intelligent than something driven by a belt!

Simon - 3/12/20 at 06:08 PM

I think the Prius has an electric pump but I have no idea how it is controlled.

Also whilst looking at them on ebay, this ad came up with an electric pump which seen to have a huge list of cars

https://www.ebay.co.uk/sch/i.html?_nkw=303367589862

aksman - 3/12/20 at 06:41 PM

quote:
Originally posted by lsdweb
The Pierburg pumps (BMW etc) are very good and you can either buy a controller (Tecomotive TinyCWA) or you could make your own (Arduino etc). My friend and I have made our own (well he has and I'm sort of copying him but using an ESP32 as it has built in CAN) and his works well. My plan is to do exactly as you said and make the pump a touch more intelligent than something driven by a belt!

The Pierburg pumps or similar look promising. I hadn't thought that production cars were using electric water pumps
The TinyCWA looks fab, but more £ than I want to pay.
Arduino etc... yes, i'm generally aware of these, but I had not thought of using them. A good Locost option!
Great info thanks

steve m - 3/12/20 at 06:52 PM

Only a suggestion, and i have no idea if it will work, or pump the correct volume or psi etc,
but what about caravan/motorhome electric water pumps
And they are 12v

steve

Mr Whippy - 3/12/20 at 07:17 PM

Not really something you want to skimp on. At best it could leave you stranded at worst cook your engine engine. Personally if the engine was designed for a mechanical pump I'll stick with that as there hugely reliable and I don't feel the benefits of an electric pump justify changing to one.

nick205 - 4/12/20 at 09:01 AM

quote:
Originally posted by Mr Whippy
Not really something you want to skimp on. At best it could leave you stranded at worst cook your engine engine. Personally if the engine was designed for a mechanical pump I'll stick with that as there hugely reliable and I don't feel the benefits of an electric pump justify changing to one.



I'm with Mr Whippy on this. Stick with a proven mechanical pump (as the engine as designed with).

If you're building an all out race car or space packaging is a particular constraint then maybe change. If you do then stick with something others have run and is therefore proven at the task. Overheated engines are not only time consuming, but usually involve more £££ and more people.

CosKev3 - 4/12/20 at 10:35 AM

I was running a Davies Craig pump and controller,until someone told me to look at the loss of performance once the coolant is under pressure,the performance drops massively.
The ltrs per hour Davies Craig quote their pumps will pump is at zero pressure, once the pressure gets up a few psi the quoted figures are half of the performance at zero pressure!

I'm now using a BMW Pierburg pump with the Tiny controller.

aksman - 4/12/20 at 10:49 AM

quote:
Originally posted by CosKev3
I was running a Davies Craig pump and controller,until someone told me to look at the loss of performance once the coolant is under pressure,the performance drops massively.
The ltrs per hour Davies Craig quote their pumps will pump is at zero pressure, once the pressure gets up a few psi the quoted figures are half of the performance at zero pressure!

I'm now using a BMW Pierburg pump with the Tiny controller.

That's interesting.
The Davies Craig EWP80 quotes 80L/min which seems impressive on the face of it.
I haven't found any performance figures for alternative pumps yet, but it sounds like something to be aware of when making comparisons.

[Edited on 4/12/20 by aksman]

aksman - 4/12/20 at 10:53 AM

quote:
Originally posted by steve m
Only a suggestion, and i have no idea if it will work, or pump the correct volume or psi etc,
but what about caravan/motorhome electric water pumps
And they are 12v

steve

I've had a quick look at those types of pump and unfortunately they don't seem powerful enough

aksman - 4/12/20 at 11:05 AM

quote:
Originally posted by Simon
I think the Prius has an electric pump but I have no idea how it is controlled.

Also whilst looking at them on ebay, this ad came up with an electric pump which seen to have a huge list of cars

https://www.ebay.co.uk/sch/i.html?_nkw=303367589862

The Prius pump looks interesting.
There is a lot of info on Youtube for general uses and there are a lot of Chinese copies for £25 on Ebay - maybe prompted by it's popularity on Youtube?
As you say, the other pump is widely used and available.
One of the key issues seems to be identifying single electric water pumps v auxiliary pumps and getting performance data for them.
Some of the DIY Youtube info suggests approx. 22L/min for the Prius.


[Edited on 4/12/20 by aksman]

CosKev3 - 4/12/20 at 11:22 AM

quote:
Originally posted by aksman
quote:
Originally posted by CosKev3
I was running a Davies Craig pump and controller,until someone told me to look at the loss of performance once the coolant is under pressure,the performance drops massively.
The ltrs per hour Davies Craig quote their pumps will pump is at zero pressure, once the pressure gets up a few psi the quoted figures are half of the performance at zero pressure!

I'm now using a BMW Pierburg pump with the Tiny controller.

That's interesting.
The Davies Craig EWP80 quotes 80L/min which seems impressive on the face of it.
I haven't found any performance figures for alternative pumps yet, but it sounds like something to be aware of when making comparisons.

[Edited on 4/12/20 by aksman]


At 7.5psi the EWP80 shows zero flow

https://daviescraig.com.au/media/2016/1596068015.EWPFlowChart24-07-19.jpg

lsdweb - 4/12/20 at 12:40 PM

I posted a chart of the flows of the Davies Craig and Pierburg pumps a while ago but somebody didn't like it and gave me hard time so I deleted it! Shame as it was useful!

lsdweb - 4/12/20 at 01:01 PM



Here it is. There are other factors involved so don't take this as exact! I added the Meziere as this is the electric pump of choice for the Type R lads (at a price!).

I have the CWA200.

Wyn

[Edited on 4/12/20 by lsdweb]

lsdweb - 4/12/20 at 01:17 PM

Fitted to my Civic.





[Edited on 4/12/20 by lsdweb]

aksman - 4/12/20 at 01:48 PM

Excellent info on the graph
The photos are useful - it's larger than I thought.
Interestingly there are a few negatives about the reliability of BMW EWP's on Youtube, but it seems to be Luddites

[Edited on 4/12/20 by aksman]

craig1410 - 4/12/20 at 03:50 PM

quote:
Originally posted by CosKev3
quote:
Originally posted by aksman
quote:
Originally posted by CosKev3
I was running a Davies Craig pump and controller,until someone told me to look at the loss of performance once the coolant is under pressure,the performance drops massively.
The ltrs per hour Davies Craig quote their pumps will pump is at zero pressure, once the pressure gets up a few psi the quoted figures are half of the performance at zero pressure!

I'm now using a BMW Pierburg pump with the Tiny controller.

That's interesting.
The Davies Craig EWP80 quotes 80L/min which seems impressive on the face of it.
I haven't found any performance figures for alternative pumps yet, but it sounds like something to be aware of when making comparisons.

[Edited on 4/12/20 by aksman]


At 7.5psi the EWP80 shows zero flow

https://daviescraig.com.au/media/2016/1596068015.EWPFlowChart24-07-19.jpg


Surely if the pump is operating in a pressurised coolant system where the pressure at the input to the pump is the same as the pressure at the output then it doesn't make any difference to the flow rate? I mean there might be a small difference due to the slight overall increase in density of the fluid but that would barely be noticeable. I think the graph here is showing the flow rate if the pressure on the output is higher than the input, which it probably will be but nowhere near 7.5psi.

This is all based on my intuition so could be wrong but I'd be surprised.

SteveWalker - 4/12/20 at 06:12 PM

You're right. It is the back-pressure that the pump sees that matters, not the system pressure.

craig1410 - 4/12/20 at 07:07 PM

quote:
Originally posted by SteveWalker
You're right. It is the back-pressure that the pump sees that matters, not the system pressure.


Yeah, backpressure is what I was thinking of. Once the backpressure reaches 7.5psi the pump will no longer be able to produce flow.

aksman - 4/12/20 at 07:24 PM

quote:
Originally posted by craig1410
quote:
Originally posted by SteveWalker
You're right. It is the back-pressure that the pump sees that matters, not the system pressure.


Yeah, backpressure is what I was thinking of. Once the backpressure reaches 7.5psi the pump will no longer be able to produce flow.

I think I understand
Is backpressure the same as resistance? The resistance that the pump has to overcome to move the water? The resistance that is associated with the diameter of pipe, length of pipe run, quantity and type of fittings etc?

[Edited on 4/12/20 by aksman]

Oddified - 4/12/20 at 07:35 PM

quote:
Originally posted by aksman
quote:
Originally posted by craig1410
quote:
Originally posted by SteveWalker
You're right. It is the back-pressure that the pump sees that matters, not the system pressure.


Yeah, backpressure is what I was thinking of. Once the backpressure reaches 7.5psi the pump will no longer be able to produce flow.

I think I understand
Is backpressure the same as resistance? The resistance that the pump has to overcome to move the water? The resistance that is associated with the diameter of pipe, length of pipe run, quantity and type of fittings etc?

[Edited on 4/12/20 by aksman]


In effect, yes.

I have a cwa100 for charge cooling dutes, very very good but not suitable for the main engine cooling.

craig1410 - 4/12/20 at 08:03 PM

quote:
Originally posted by aksman
quote:
Originally posted by craig1410
quote:
Originally posted by SteveWalker
You're right. It is the back-pressure that the pump sees that matters, not the system pressure.


Yeah, backpressure is what I was thinking of. Once the backpressure reaches 7.5psi the pump will no longer be able to produce flow.

I think I understand
Is backpressure the same as resistance? The resistance that the pump has to overcome to move the water? The resistance that is associated with the diameter of pipe, length of pipe run, quantity and type of fittings etc?

[Edited on 4/12/20 by aksman]


Picture it like this. If you fitted the pump into a U shaped piece of tubing that was full of water but open at both ends with those ends pointing upwards. If you started the pump you would expect the water level to drop in one vertical leg and rise in the other. The difference in levels represents the pressure difference across the pump. 7.5psi is just over 0.5 bar which is equivalent to approximately 5m of difference in the level of the water in the two legs.

Another way to think of it is that the pump has a certain amount of “traction” just like a car tyre has only so much traction before it will start to spin.

HTH

number-1 - 4/12/20 at 09:17 PM

Ive read the above and the science is too much for me.....but....ive used Davies craig ewp on a single seater Yamaha engine BEC for track and it cured an overheating issue i had (due to the extra 3 metres in cooling pipes needed) and also on a SC zetec engine and it worked a treat so would recommend the davies craig ewp and controller

just my 2p worth

CosKev3 - 5/12/20 at 01:58 PM

quote:
Originally posted by craig1410
quote:
Originally posted by CosKev3
quote:
Originally posted by aksman
quote:
Originally posted by CosKev3
I was running a Davies Craig pump and controller,until someone told me to look at the loss of performance once the coolant is under pressure,the performance drops massively.
The ltrs per hour Davies Craig quote their pumps will pump is at zero pressure, once the pressure gets up a few psi the quoted figures are half of the performance at zero pressure!

I'm now using a BMW Pierburg pump with the Tiny controller.

That's interesting.
The Davies Craig EWP80 quotes 80L/min which seems impressive on the face of it.
I haven't found any performance figures for alternative pumps yet, but it sounds like something to be aware of when making comparisons.

[Edited on 4/12/20 by aksman]


At 7.5psi the EWP80 shows zero flow

https://daviescraig.com.au/media/2016/1596068015.EWPFlowChart24-07-19.jpg


Surely if the pump is operating in a pressurised coolant system where the pressure at the input to the pump is the same as the pressure at the output then it doesn't make any difference to the flow rate? I mean there might be a small difference due to the slight overall increase in density of the fluid but that would barely be noticeable. I think the graph here is showing the flow rate if the pressure on the output is higher than the input, which it probably will be but nowhere near 7.5psi.

This is all based on my intuition so could be wrong but I'd be surprised.


The person that warned me about the flow drop under pressure had a Cosworth engine on a test bed with multiple probes fitted to the head.
They experienced hot spots in the head at higher temps which caused the head to go porous due to micro boiling.
The head was cut apart to investigate.
The cause was lack of flow from the Davies Craig EWP as they refitted the standard mechanical pump and it was ok running that.

mgb281 - 5/12/20 at 05:04 PM

I was looking at this myself and have found out the following; that if your ECU has spare PWM outputs you can control an electric water pump from there, the example I have been given is zero until 6c then 25% until 50c then 75% at 90c then 100% at 95c. Obviously you would adjust duty rates according to your target temperature. Using your ECU or the Davies Craig controller enables you to do away with your thermostat, so the hot water will leave the engine ang go straight to the radiator. The Davies Craig controller does enable you to allow both pump and fan to run for up to two minutes after engine switch off to prevent heat soak. There is very little back pressure with a system like this due to the straight through design and providing you have a header tank that keeps the system full then there is no head of water to pump..
As for reliability then you will not find thousands of owners on the forums complaining about failed pumps, just a few who would have complained about a mechanical one as well.

aksman - 5/12/20 at 06:37 PM

quote:
Originally posted by mgb281
I was looking at this myself and have found out the following; that if your ECU has spare PWM outputs you can control an electric water pump from there, the example I have been given is zero until 6c then 25% until 50c then 75% at 90c then 100% at 95c. Obviously you would adjust duty rates according to your target temperature. Using your ECU or the Davies Craig controller enables you to do away with your thermostat, so the hot water will leave the engine ang go straight to the radiator. The Davies Craig controller does enable you to allow both pump and fan to run for up to two minutes after engine switch off to prevent heat soak. There is very little back pressure with a system like this due to the straight through design and providing you have a header tank that keeps the system full then there is no head of water to pump..
As for reliability then you will not find thousands of owners on the forums complaining about failed pumps, just a few who would have complained about a mechanical one as well.

Some good information and ideas have being provided by everyone to date thanks
Here's a summary of where I am right now.
I don't have an ECU myself but it's handy to know if I upgrade in the future.
The Davies Craig pump and controller has a lot going for it and whilst expensive new, it seems to be good value for money when you factor everything in.
A used Pierburg CWA200 + Davies Craig Controller or Tecmotive Tiny CWA is also looking like a good value alternative.
If I ever find myself with time on my hands then it would be interesting to look at using an Arduino.
It looks like the Auxiliary Pumps are a non starter as they would be underpowered.

CosKev3 - 5/12/20 at 08:14 PM

quote:
Originally posted by aksman
quote:
Originally posted by mgb281
I was looking at this myself and have found out the following; that if your ECU has spare PWM outputs you can control an electric water pump from there, the example I have been given is zero until 6c then 25% until 50c then 75% at 90c then 100% at 95c. Obviously you would adjust duty rates according to your target temperature. Using your ECU or the Davies Craig controller enables you to do away with your thermostat, so the hot water will leave the engine ang go straight to the radiator. The Davies Craig controller does enable you to allow both pump and fan to run for up to two minutes after engine switch off to prevent heat soak. There is very little back pressure with a system like this due to the straight through design and providing you have a header tank that keeps the system full then there is no head of water to pump..
As for reliability then you will not find thousands of owners on the forums complaining about failed pumps, just a few who would have complained about a mechanical one as well.

Some good information and ideas have being provided by everyone to date thanks
Here's a summary of where I am right now.
I don't have an ECU myself but it's handy to know if I upgrade in the future.
The Davies Craig pump and controller has a lot going for it and whilst expensive new, it seems to be good value for money when you factor everything in.
A used Pierburg CWA200 + Davies Craig Controller or Tecmotive Tiny CWA is also looking like a good value alternative.
If I ever find myself with time on my hands then it would be interesting to look at using an Arduino.
It looks like the Auxiliary Pumps are a non starter as they would be underpowered.


I've got two genuine Pierburg CWA200's,one is brand new unused in the box I would let go for £220,or the one I've used for 12 months that's done a couple of thousand miles for £150.

Don't be tempted buy a copy of the Pierburg, performance is not as good,and the one I bought didn't work at all

I run the Tecmotive Tiny controller,would recommend it over the Davies Craig one.
Not a fancy touch screen like the Davies Craig,but I like the fact the Tiny one shows you via the line of LEDs how fast the pump is running.
Then when it switches the fan on all the LEDs flash while fan is on.

lsdweb - 6/12/20 at 12:19 PM

My homebuilt controller (ESP32 based) is setup to work in four different phases - warm up(blue) where pump speed is low, normal (green) for normal operating temperatures, an amber phase where it's getting a touch to hot and red when temp is too high.

The controller takes coolant temp, rpm, throttle position and battery voltage from the ECU via CAN and varies the PWM according to the four phases.

The controller also controls the alternator, switching it 'off' at high throttle openings unless battery voltage is too low.

There'll be an override switch for both water pump and alternator.

This is all working on the bench (with a simulator connected to the Emerald ECU) and my friend has his (arduino based) working on the car. This is one of four arduinos on his car I think - one in each engine ECU (Speeduino), water pump controller and another one for something I've forgotten!

Wyn

lsdweb - 6/12/20 at 12:43 PM

Here's a quick video of it 'on the bench'. The top number is RPM and the bottom is coolant temp. The different phases and pump speeds are shown by the colour of the display (I somehow missed out the amber phase )


https://youtu.be/jWhh1tJv50g

aksman - 8/12/20 at 05:10 PM

quote:
Originally posted by lsdweb
My homebuilt controller (ESP32 based) is setup to work in four different phases - warm up(blue) where pump speed is low, normal (green) for normal operating temperatures, an amber phase where it's getting a touch to hot and red when temp is too high.

The controller takes coolant temp, rpm, throttle position and battery voltage from the ECU via CAN and varies the PWM according to the four phases.

The controller also controls the alternator, switching it 'off' at high throttle openings unless battery voltage is too low.

There'll be an override switch for both water pump and alternator.

This is all working on the bench (with a simulator connected to the Emerald ECU) and my friend has his (arduino based) working on the car. This is one of four arduinos on his car I think - one in each engine ECU (Speeduino), water pump controller and another one for something I've forgotten!

Wyn

It sounds like an excellent set-up Wyn and shows what can be done with today's technology.
Unfortunately ESP32 is too advanced for me.
I like the sound of your mate's 4 arduinos.
Has he posted any details about them anywhere?
Alan

lsdweb - 8/12/20 at 09:37 PM

Hi Alan.

Apologies for highjacking your thread! The ESP32 is no different from an Arduino really. It was just an easier choice for the CAN setup. And I'm hopeless with these things but trying to learn (old dogs new tricks and all that!)

I'll try and get my pal Lyndon to come on here - he's well suited to this site which you can see from somebody who has two engine ECUs in the car! His Arduino based pump controller works off temperature sensors so no CAN in sight!

Regards

Wyn